Conventionally, a steam generating apparatus that uses steam and that is designed for use in a humidifying air conditioner or a humidifying cooker is so constructed as to supply steam in the following manner: water fed from a reservoir tank is vaporized in a vaporizing container heated with a heater or the like.
In such a steam generating apparatus, as time passes, substances, such as calcium, dissolved in the water fed from the reservoir tank are condensed inside the vaporizing container until eventually, when their concentrations become higher than their solubility, they are deposited in the form of scale. This may clog the steam outlet, or may attach to the interior wall surface of the vaporizing container, leading to diminished vaporizing performance.
Patent Publication 1 listed below discloses, with a view to overcoming such clogging and diminishing of vaporizing performance due to scale, a construction in which the water left in the vaporizing container is drained out of it and the vaporizing container is then heated and boiled with no water in it (empty-boiled) for a predetermined length of time. This permits the scale to be forcibly removed from the vaporizing container thanks to the difference in thermal expansion coefficient between them.
Patent Publication 1: Japanese Patent Application Laid-Open No. H5-231604